Opponents will know what choices opponents earlier in turn order made, although cards chosen to be discarded this way won't be revealed until they're discarded at the end of the process
EDH, 60 card casual, standard, or Eldrazi (modern), it doesn't really matter, as long as everyone is ok with the decks being played
Wishiwashi #240 Pokemon Cosmic Eclipse Keep track of your collection value over time
Pokemon Japanese Shiny Star V card list & price guide
This Ho-Oh card is a great choice if you enjoy the Pokemon, especially if you don't mind settling for one in less-than-ideal condition
Many cards can reduce casting costs by sacrificing something as well, but the fact that you can sacrifice a treasure token for mana to essentially get a reduction of 3 mana is incredible